The stereoselective formation of C–O, C–S and C–N bonds by the reaction of phenols, thiols and amines with activated alkynes is described. The reactions are successfully conducted in water with excellent yields at room temperature. The lack of organic solvent use in the work-up procedure, the short reaction time and the environmentally benign mild reaction conditions are advantages of this method.
Metal-free catalytic cascade to chromones: direct coupling of salicylaldehydes and activated alkynes triggered by aryloxyl radicals
作者:Ping Wang、Zhongfeng Li、Shengli Cao、Honghua Rao
DOI:10.1039/c5ra24634b
日期:——
The first intermolecular addition reaction of aryloxylradicals to CC bonds was disclosed, which can afford biologically important chromone scaffolds via a PhNMe3I-catalyzed direct coupling of readily available salicylaldehydes and activated internal alkynes in only one step, and can tolerate a range of catalytically reactive functional groups.
Microwave assisted synthesis of hydroxychromenes using imidazole-functionalized silica nanoparticles as a catalyst under solvent-free conditions
作者:Hassan Valizadeh、Leila Dinparast、Saeideh Noorshargh、Majid M. Heravi
DOI:10.1016/j.crci.2015.11.010
日期:2016.3
Résumé A microwave-assisted reaction of various salicylaldehydes with dialkyl acetylenedicarboxylates mediated by imidazole-functionalized silica nanoparticles is successfully and rapidly achieved to afford the corresponding hydroxychromenes in high to excellent yields under solvent-free conditions.
Reaction between <i>ortho</i>‐Hydroxy Aromatic Aldehydes and Dialkyl Acetylenedicarboxylates in the Presence of Silica Gel in Solvent‐Free Conditions
作者:Nader Noshiranzadeh、Ali Ramazani
DOI:10.1080/00397910701545486
日期:2007.9.1
Abstract A two‐component condensation reaction between an ortho‐hydroxy aromatic aldehyde and an electron‐poor acetylenic ester efficiently provides fully substituted electron‐poor aryl vinyl ethers and chromenes in a one‐pot reaction in the presence of silica‐gel in solvent‐free conditions.